With the development of medical technology, medical scan increasingly becomes an important tool for diagnosis and treatment in many medical applications. For example, Computed Tomography (CT) has been widely used for diagnosis examination and radiation therapy for patients. In the CT scan, as a rule, a marker will be set on the body of a patient. The marker can be used for different purposes, such as the registration between CT images and MRI images, the calibration of image alignment, or the motion correction for images, etc.
U.S. Pat. No. 8,055,049 describes a method for correcting motions of a patient during a CT scan with markers. In the method, markers are set on the patient's body in a fixed manner, then a CT scan begins, and a motion data set is obtained based on the projection positions of the markers. Lastly, a CT image is reconstructed with the motion data set.
U.S. Pat. No. 5,662,111 describes another method for using markers. In the method, markers are set at places that have relatively fixed positions with respect to tissues and structures of the patient's body, then the known coordinates of the markers are used to determine the coordinates of all the other identifiable points in the stereotactic coordinate system.
For more description of the use of markers in the medical scan, see U.S. Pat. No. 6,419,680, U.S. Pat. No. 7,697,738, U.S. Pat. No. 6,052,477, U.S. Pat. No. 4,945,914, and U.S. Pat. No. 4,991,579.
The contents of these patents are incorporated into the present application through citation.
However, in the above prior arts, markers are usually only used as reference points, and detection or application of the shape, size or orientation of the markers is not taken into consideration.
On the other hand, when performing a CT scan, scout scan needs to be performed before manually setting parameters based on the scout scan and performing the follow-up scan. However, the manual setting is inefficient, and manual factors often lead to impreciseness.
The CT scan in the prior art also involves defects in other aspects. Therefore, it is desired that there is an improved solution to increase one or more aspects of the prior art, e.g. to improve the use of the markers, or increase the efficiency and preciseness of parameter settings.